Wireless Local Area Networks (WLANs) include multiple wireless communication devices that communicate over one or more wireless channels. A wireless communication device called an access point (AP) provides connectivity with a network, such as the Internet, to other wireless communication devices, e.g., client stations or access terminals (AT). Various examples of wireless communication devices include mobile phones, smart phones, wireless routers, and wireless hubs. In some cases, wireless communication electronics are integrated with data processing equipment such as laptops, personal digital assistants, and computers.
Wireless communication systems such as WLANs can use one or more wireless communication technologies such as orthogonal frequency division multiplexing (OFDM). In an OFDM based wireless communication system, a data stream can be split into multiple data substreams. Such data substreams are sent over different OFDM subcarriers, which can be referred to as tones or frequency tones. WLANs such as those defined in the Institute of Electrical and Electronics Engineers (IEEE) wireless communications standards, e.g., IEEE 802.11a, IEEE 802.11n, and IEEE 802.11ac, can use OFDM to transmit and receive signals.